Protective effect of lipoic acid on oxidative and peroxidative damage in cyclosporine A-induced renal toxicity

Pomegranate attenuates kidney injury in cyclosporine-induced nephrotoxicity in rats by suppressing oxidative stress

To investigate the effect of pomegranate juice (PJ) on the cyclosporine (CsA)-induced nephrotoxicity in rats, 80 rats were divided into four groups. The first group was regarded a negative control group, and the others were as follows: group 2 (CsA group) received CsA in a dose of 25 mg/kg/day orally, group 3 (treated group) received CsA in a dose of 25 mg/kg/day plus 2.5 mL/day of PJ, and group 4 (PJ group) received 2.5 mL of PJ daily. By the end of the 21st day, plasma creatinine, blood urea nitrogen (BUN), creatinine clearance, urinary KIM-1, and NGAL were determined. Histopathological investigation and the determination of malondialdehyde and antioxidant enzymes were analyzed in kidney tissues. The results show that plasma creatinine, BUN, creatinine clearance, and kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin were significantly altered in the CsA group. The supplement of PJ attenuated the alteration in these parameters. The treatment with PJ also prohibits the CsA-induced alteration in the histopathology, lipid peroxidation, and antioxidant enzymes. We can conclude that PJ protects against CsA-induced nephrotoxicity due to its antioxidant effects.

α-Lipoic Acid Protects against Cyclosporine A-Induced Hepatic Toxicity in Rats: Effect on Oxidative Stress, Inflammation, and Apoptosis

The clinical application of cyclosporine A (CsA) as an immunosuppressive agent is limited by its organ toxicity. We aimed to evaluate the effectiveness of α-lipoic acid against CsA-induced hepatotoxicity and to delineate the underlying molecular mechanisms. Male Wistar rats (n = 24, 8 per each group) received the vehicle, CsA (25 mg/kg) and/or ALA (100 mg/kg, p.o.) for 3 weeks. Biochemical markers of liver function (serum ALT, AST, ALP < GGT), oxidative stress (MDA, TAC, SOD, GSH, Nrf2/HO-1), inflammation (NF-κB, CD68, iNOS, NO, COX-2), and apoptosis (caspase-3) were assessed in serum and tissue. Liver histological analysis using H&E and Sirius red was performed. The development of liver injury in CsA-treated animals was indicated by elevated levels of liver enzymes, oxidants/antioxidants imbalance, inflammatory cells infiltration, up-regulated expression of inflammatory mediators, and apoptosis. These changes were associated with altered architecture of hepatic cells and fibrous connective tissue. ALA co-administration protected against CsA-induced liver damage and ameliorated biochemical changes and cellular injury. In conclusion, ALA demonstrated hepatoprotective potential against CsA-induced liver injury through combating oxidative stress, inflammation, and apoptosis, highlighting ALA as a valuable adjunct to CsA therapy.

Prior intake of Brazil nuts attenuates renal injury induced by ischemia and reperfusion

Introduction:

Ischemia-reperfusion (IR) injury results from inflammation and oxidative stress, among other factors. Because of its anti-inflammatory and antioxidant properties, the Brazil nut (BN) might attenuate IR renal injury.

Objective:

The aim of the present study was to investigate whether the intake of BN prevents or reduces IR kidney injury and inflammation, improving renal function and decreasing oxidative stress.

Methods:

Male Wistar rats were distributed into six groups (N=6/group): SHAM (control), SHAM treated with 75 or 150 mg of BN, IR, and IR treated with 75 or 150 mg of BN. The IR procedure consisted of right nephrectomy and occlusion of the left renal artery with a non-traumatic vascular clamp for 30 min. BN was given daily and individually for 7 days before surgery (SHAM or IR) and maintained until animal sacrifice (48h after surgery). We evaluated the following parameters: plasma creatinine, urea, and phosphorus; proteinuria, urinary output, and creatinine clearance; plasmatic TBARS and TEAC; kidney expression of iNOS and nitrotyrosine, and macrophage influx.

Results:

Pre-treatment with 75 mg of BN attenuated IR-induced renal changes, with elevation of creatinine clearance and urinary output, reducing proteinuria, urea, and plasmatic phosphorus as well as reducing kidney expression of iNOS, nitrotyrosine, and macrophage influx.

Conclusion:

Low intake of BN prior to IR-induced kidney injury improves renal function by inhibition of macrophage infiltration and oxidative stress.

Alpha-lipoic acid ameliorates the epithelial mesenchymal transition induced by unilateral ureteral obstruction in mice

The epithelial-to-mesenchymal transition (EMT) is one of mechanisms that induce renal interstitial fibrosis. Understanding EMT in renal fibrosis has important therapeutic implications for patients with kidney disease. Alpha-lipoic acid (ALA) is a natural compound with antioxidant properties. Studies for ALA are performed in acute kidney injury with renal tubular apoptosis, renal inflammation, and oxidative stress. We investigated the effects of ALA on EMT-mediated renal interstitial fibrosis in mice with unilateral ureteral obstruction (UUO). UUO mice developed severe tubular atrophy and tubulointerstitial fibrosis, with a robust EMT response and ECM deposition after 7 postoperative days. In contrast, ALA-treated UUO mice showed only moderate injury and minimal fibrosis and also larger reductions in the expression of ECM proteins, inflammatory factors, and EMT markers. ALA was shown to be involved in the suppression of infiltrating macrophages associated with EMT and the progression of interstitial fibrosis. It also lessened the destruction of the tubular basement membrane, by reducing the expression of matrix metalloproteinases. This is the first study to show that ALA modulates EMT in a UUO mouse model. Our results suggest that ALA merits further exploration as a therapeutic agent in the prevention and treatment of chronic kidney disease.

Endothelin ETA receptor/lipid peroxides/COX-2/TGF-β1 signalling underlies aggravated nephrotoxicity caused by cyclosporine plus indomethacin in rats

BACKGROUND AND PURPOSE

Cyclosporine (CSA) and non-steroidal anti-inflammatory drugs (NSAIDs) are co-prescribed for some arthritic conditions. We tested the hypothesis that this combined regimen elicits exaggerated nephrotoxicity in rats via the up-regulation of endothelin (ET) receptor signalling.

EXPERIMENTAL APPROACH

The effects of a 10 day treatment with CSA (20 mg · kg(-1) · day(-1)), indomethacin (5 mg · kg(-1) · day(-1)) or their combination on renal biochemical, inflammatory, oxidative and structural profiles were assessed. The roles of ETA receptor and COX-2 pathways in the interaction were evaluated.

KEY RESULTS

Oral treatment with CSA or indomethacin elevated serum urea and creatinine, caused renal tubular atrophy and interstitial fibrosis, increased renal TGF-β1, and reduced immunohistochemical expressions of ETA receptors and COX-2. CSA, but not indomethacin, increased renal ET-1, the lipid peroxidation product malondialdehyde (MDA) and GSH activity. Compared with individual treatments, simultaneous CSA/indomethacin exposure caused: (i) greater elevations in serum creatinine and renal MDA; (ii) loss of the compensatory increase in GSH; (iii) renal infiltration of inflammatory cells and worsening of fibrotic and necrotic profiles; and (iv) increased renal ET-1 and decreased ETA receptor and COX-2 expressions. Blockade of ETA receptors by atrasentan ameliorated the biochemical, structural, inflammatory and oxidative abnormalities caused by the CSA/indomethacin regimen. Furthermore, atrasentan partly reversed the CSA/indomethacin-evoked reductions in the expression of ETA receptor and COX-2 protein.

CONCLUSIONS AND IMPLICATIONS

The exaggerated oxidative insult and associated dysregulation of the ETA receptor/COX-2/TGF-β1 signalling might account for the aggravated nephrotoxicity caused by the CSA/indomethacin regimen. The potential renoprotective effect of ETA receptor antagonism might be exploited therapeutically.

Use of antioxidants to prevent cyclosporine a toxicity

Cyclosporine A (CsA) is a potent immunosuppressor that is widely used in transplant surgery and the treatment of several autoimmune diseases. However, major side effects of CsA such as nephrotoxicity, hepatotoxicity, neurotoxicity and cardiovascular diseases have substantially limited its usage. Although molecular mechanisms underlying these adverse effects are not clearly understood, there is some evidence that suggests involvement of reactive oxygen species (ROS) . In parallel, protective effects of various antioxidants have been demonstrated by many research groups. Extensive studies of CsA-induced nephrotoxcity have confirmed that the antioxidants can restore the damaged function and structure of kidney. Subsequently, there have appeared numerous reports to demonstrate the positive antioxidant effects on liver and other organ damages by CsA. It may be timely to review the ideas to envisage the relationship between ROS and the CsA-induced toxicity. This review is comprised of a brief description of the immunosuppressive action and the secondary effects of CsA, and a synopsis of reports regarding the antioxidant treatments against the ROS-linked CsA toxicity. A plethora of recent reports suggest that antioxidants can help reduce many CsA’s adverse effects and therefore might help develop more effective CsA treatment regimens.

Alpha-lipoic acid attenuates renal injury in rats with obstructive nephropathy

This study was established to determine the possible protective effects of alpha-lipoic acid (ALA), a powerful antioxidant, on renal injury in obstructive nephropathy. Male Sprague-Dawley rats were assigned into sham-operated unilateral ureteral obstruction (UUO) and UUO treated with ALA groups. ALA 60 mg/kg was injected intraperitoneally 2 days before UUO induction and continued afterward for 7 days. Renal function, oxidative stress markers, nitric oxide, transforming growth factor-1 (TGF-β1), and histological changes were evaluated at the end of the experiment. Obstruction of the ureter resulted in renal dysfunction as indicated by significant increases in blood urea nitrogen and serum creatinine. Nonobstructed contralateral kidneys in all groups examined did not show any morphological or biochemical alterations. In untreated UUO group, the obstructed kidney developed marked hydronephrosis, leukocyte infiltration, and severe interstitial fibrosis. These functional and structural changes were associated with significant increases in tissue levels of malondialdehyde, nitric oxide, and TGF-β1 but decreases in reduced glutathione and total antioxidant capacity. Pretreatment with ALA significantly minimized all the changes elicited by ureteral obstruction. These findings demonstrate that ALA supplementation attenuates renal injury in rats with obstructive nephropathy and further suggest that oxidative stress inhibition is likely to be involved in the beneficial effects of this compound.

Inhibitory effect of α-lipoic acid on thioacetamide-induced tumor promotion through suppression of inflammatory cell responses in a two-stage hepatocarcinogenesis model in rats

To investigate the protective effect of α-lipoic acid (a-LA) on the hepatocarcinogenic process promoted by thioacetamide (TAA), we used a two-stage liver carcinogenesis model in N-diethylnitrosamine (DEN)-initiated and TAA-promoted rats. We examined the modifying effect of co-administered a-LA on the liver tissue environment surrounding preneoplastic hepatocellular lesions, with particular focus on hepatic macrophages and the mechanism behind the decrease in apoptosis of cells surrounding preneoplastic hepatocellular lesions during the early stages of hepatocellular tumor promotion. TAA increased the number and area of glutathione S-transferase placental form (GST-P)(+) liver cell foci and the numbers of proliferating and apoptotic cells in the liver. Co-administration with a-LA suppressed these effects. TAA also increased the numbers of ED2(+), cyclooxygenase-2(+), and heme oxygenase-1(+) hepatic macrophages as well as the number of CD3(+) lymphocytes. These effects were also suppressed by a-LA. Transcript levels of some inflammation-related genes were upregulated by TAA and downregulated by a-LA in real-time RT-PCR analysis. Outside the GST-P(+) foci, a-LA reduced the numbers of apoptotic cells, active caspase-8(+) cells and death receptor (DR)-5(+) cells. These results suggest that hepatic macrophages producing proinflammatory factors may be activated in TAA-induced tumor promotion. a-LA may suppress tumor-promoting activity by suppressing the activation of these macrophages and the subsequent inflammatory responses. Furthermore, a-LA may suppress tumor-promoting activity by suppressing the DR5-mediated extrinsic pathway of apoptosis and the subsequent regeneration of liver cells outside GST-P(+) foci.

Involvement of multiple cell cycle aberrations in early preneoplastic liver cell lesions by tumor promotion with thioacetamide in a two-stage rat hepatocarcinogenesis model

Thioacetamide (TAA) induces oxidative stress and hepatocarcinogenicity in rats. We previously reported that TAA promotion caused various disruptions in cell cycle protein expression in rats, including downregulation of p16(Ink4a), which is associated with intraexonic hypermethylation in hepatocellular proliferative lesions. This study further investigated the contribution of cell cycle aberrations associated with early hepatocarcinogenic processes induced by TAA using antioxidants, enzymatically modified isoquercitrin (EMIQ) and α-lipoic acid (ALA), in a two-stage rat hepatocarcinogenesis model. TAA-promotion after initiation with N-diethylnitrosamine increased the number and area of hepatocellular foci immunoreactive for glutathione S-transferase placental form (GST-P) and the numbers of proliferating and apoptotic cells. Co-treatment with EMIQ and ALA suppressed these increases. TAA-induced formation of p16(Ink4a-) foci in concordance with GST-P(+) foci was not suppressed by co-treatment with EMIQ or ALA. TAA-promotion increased cellular distributions of cell proliferation marker Ki-67, G2/M and spindle checkpoint proteins (phosphorylated checkpoint kinase 1 and Mad2), the DNA damage-related protein phosphorylated histone H2AX, and G2-M phase-related proteins (topoisomerase IIα, phosphorylated histone H3 and Cdc2) within GST-P(+) foci, and co-treatment with EMIQ or ALA suppressed these increases. These results suggest that downregulation of p16(Ink4a) may allow selective proliferation of preneoplastic cells by TAA promotion. However, antioxidants did not counteract this gene control. Moreover, effective suppression of TAA-induced cellular population changes within preneoplastic lesions by antioxidants may reflect facilitation of cell cycling and accumulation of DNA damage causing the activation of cell cycle checkpoints, leading to G2 and M phase arrest at the early stages of hepatocarcinogenesis promoted by TAA.

The effect of alpha-lipoic acid on mitochondrial superoxide and glucocorticoid-induced hypertension

Aims. To examine the effect of alpha-lipoic acid, an antioxidant with mitochondrial superoxide inhibitory properties, on adrenocorticotrophic hormone- (ACTH-HT) and dexamethasone-induced hypertensions (DEX-HT) in rats and if any antihypertensive effect is mediated via mitochondrial superoxide inhibition. Methods. In a prevention study, rats received ground food or alpha-lipoic-acid-laced food (10 mg/rat/day) for 15 nights. Saline, adrenocorticotrophic hormone (ACTH, 0.2 mg/kg/day), or dexamethasone (DEX, 10 μg/rat/day) was injected subcutaneously from day 5 to day 11. In a reversal study, rats received alpha-lipoic-acid-laced food 4 days after commencement of saline or DEX. Tail-cuff systolic blood pressure (SBP) was measured second daily. Kidney mitochondrial superoxide was examined using (MitoSOX) Red (MitoSOX) via flow cytometry. Results. SBP was increased by ACTH (P < 0.0005) and DEX (P < 0.0005). Alpha-lipoic acid alone did not alter SBP. With alpha-lipoic acid pretreatment, SBP was increased by ACTH (P′ < 0.005) but not by DEX. Alpha-lipoic partially prevented ACTH-HT (P′ < 0.0005) and fully prevented DEX-HT (P′ < 0.0005) but failed to reverse DEX-HT. ACTH and DEX did not increase MitoSOX signal. In ACTH-hypertensive rats, high-dose alpha-lipoic acid (100 mg/rat/day) did not decrease SBP further but raised MitoSOX signal (P < 0.001), suggesting prooxidant activity. Conclusion. Glucocorticoid-induced hypertension in rats is prevented by alpha-lipoic acid via mechanisms other than mitochondrial superoxide reduction.

In vivo toxicological evaluation of Anisomycin

Anisomycin is a pyrrolidine antibiotic isolated from Streptomyces griseolus. Recent studies have shown that Anisomycin as a novel immunosuppressive agent is superior to Cyclosporine A (J. Immunother. 31, 858-870, 2008). In order to make toxicological evaluation of Anisomycin, acute and four-week continuously intravenous toxicity studies were performed in mice. IC(50) value tested on peripheral lymphocytes was 25.44 ng/ml. The calculated LD(50) for Anisomycin was 119.64 mg/kg. The mice were intravenously injected through mouse tail vein with a total dose of 5, 15, 30 and 60 mg/kg/mice of Anisomycin every other day for 4 weeks. Just in the high-dose mice, death of three mice happened and body weight of the mice was significantly decreased. Statistically significant changes in organ index included increases in ratios of the spleen, liver, lung and brain to the body weight, and decrease in ratio of the thymus to the body weight. Changes in clinical biochemistry parameters included increases in the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, and decreases in the glucose (GLU) activity. The distinct inflammation appeared in the lung, liver and kidney, and the number and size of megakaryocytes in the spleen were significantly increased. Anisomycin did not induce formation of the peripheral blood micronucleus, but increased the number of micronucleated polychromatic erythrocytes in bone marrow and sperm aberrations. However, the above aberrant changes occurred only in the mice treated with the high-dose Anisomycin. These results indicate that although Anisomycin has no significant side effects at effectively therapeutic doses, its over-dosage may lead to toxicity, particularly pulmo-, nephro- and hepato-toxicity.

Differential efficiency of simvastatin and lipoic acid treatments on Bothrops jararaca envenomation-induced acute kidney injury in mice

Snake bite accidents by Bothrops genus is an important public health issue in Brazil and one of its most serious complications is the acute kidney injury (AKI). Here we evaluated the effects of Bothrops jararaca venom (vBj) and the treatments with lipoic acid (LA) and simvastatin (SA) on renal function, aminopeptidase (AP) activities and renal redox status. Primordial events for establishment of AKI by vBj were hyperuricemia, hypercreatinemia, urinary hyperosmolality, renal oxidative stress and reduction of hematocrit and protein content in the membrane of renal cortex and medulla and in the plasma. In the renal cortex and medulla the changes caused by vBj in soluble and membrane-bound AP activities had a similar pattern. The beneficial effects of LA and SA on envenomed mice were similar on the hyperuricemia, renal oxidative stress and reduction of hematocrit. LA mitigated the hypercreatinemia, but exacerbated the urinary urea and creatinine, whereas SA mitigated the decrease of plasma urea, urinary hyperosmolality and hypercreatinuria induced by vBj. The beneficial effects of LA and especially of SA on renal effects of vBj open a new perspective for clinical investigations of these drugs as coadjuvant agents in the serotherapy of Bothrops envenomation.

Tinospora cordifolia ameliorates urotoxic effect of cyclophosphamide by modulating GSH and cytokine levels

Cyclophosphamide (CP) is a commonly used anti-cancer drug which causes toxicity by its reactive metabolites. In this study we investigated the effect of Tinospora cordifolia on urotoxicity induced by acute dose of CP using Swiss albino mice model. Administration of an alcoholic extract of the plant T. cordifolia (Family: Menispermaceae) (200 mg/kg i.p.) for 5 days reduced CP (1.5 mmol/kg body wt. i.p.) induced urotoxicity as evident from the morphological analysis of bladder, decreased the relative bladder and liver weights and also decreased level of urea nitrogen and protein in blood as well as urine. Severely inflamed and dark coloured urinary bladders of the CP alone treated animals were found to be normalized by the treatment of T. cordifolia. GSH content, which was drastically reduced by CP administration in both bladder and liver was enhanced by treatment with T. cordifolia. Histopathological analysis of the bladder of CP alone-treated group showed severe necrotic damage where as the T. cordifolia-treated group showed normal bladder architecture. The lowered levels of cytokines IFN-γ, IL-2, after CP treatment were found to be increased in treated animals. At the same time the level of pro-inflammatory cytokine TNF-α, which was elevated during CP administration, was significantly reduced by extract administration. This study clearly demonstrates uroprotective role of T. cordifolia from CP induced toxicities by modulating GSH and pro-inflammatory cytokine levels.

Macrophage depletion attenuates chronic cyclosporine A nephrotoxicity

BACKGROUND

Cyclosporine A (CsA)-induced chronic nephrotoxicity is characterized by renal dysfunction and interstitial fibrosis. Early and progressive renal macrophage influx, correlating with latter interstitial fibrotic areas, has been associated with CsA treatment. This study investigated the role of macrophages, the nitric oxide (NO) pathway, and the oxidative stress on chronic CsA nephrotoxicity.

METHODS

The macrophages were depleted by clodronate liposomes. Animals were distributed into four groups: vehicle (olive oil for 21 days), CsA 7.5 mg/kg per day (21 days), CsA plus clodronate (5 mg/mL intraperitoneally on days -4, 1, 4, 11, and 18 of CsA treatment), or vehicle plus clodronate. On day 22, glomerular filtration rate, renal blood flow, renal tubulointerstitial fibrosis, CsA blood levels, serum malondialdehyde and renal tissue immunohistochemistry for macrophages, inducible NO synthase, transforming growth factor-beta, nuclear factor-kbeta, alpha-smooth muscle actin, vimentin, and nitrotyrosine were assessed.

RESULTS

CsA-induced increase in the macrophage was prevented by clodronate. Macrophage depletion attenuated the reductions in the glomerular filtration rate and renal blood flow, the development of tubulointerstitial fibrosis, malondialdehyde increase and increases in nuclear factor-kbeta, transforming growth factor-beta, vimentin, inducible NO synthase, and nitrotyrosine expression provoked by CsA. Clodronate did not affect alpha-smooth muscle actin expression and CsA blood levels.

CONCLUSIONS

Renal macrophage influx plays an important role in CsA-induced chronic nephrotoxicity. The NO pathway and oxidative stress are likely mechanisms involved in the genesis of this form of renal injury.

Protective effect of COMP-angiopoietin-1 on cyclosporine-induced renal injury in mice

BACKGROUND

Peritubular capillary injury induces chronic hypoxia in the renal tubulointerstitium, and renal peritubular capillary dysfunction is an early event that contributes to tubulointerstitial fibrosis. Cyclosporine A (CsA) is a potent immunosuppressant and improves survival of renal allografts. However, the limitation of CsA use is chronic nephrotoxicity. A soluble, stable and potent angiopoietin-1 (Ang1) variant, cartilage oligomeric matrix protein (COMP)-Ang1 has been developed. We investigated whether COMP-Ang1 ameliorates CsA-induced renal injury.

METHODS

CsA-treated mice were injected with recombinant adenovirus expressing either COMP-Ang1 or LacZ. Histology, inflammatory, haemodynamic and fibrotic parameters, and signalling pathway were evaluated.

RESULTS

Histologic examination showed that COMP-Ang1 significantly decreased CsA-induced tubular damage and tubulointerstitial fibrosis. CsA-induced increases in macrophage infiltration and expression of MCP-1 and ICAM-1 after CsA treatment were significantly reduced by COMP-Ang1. Treatment with COMP-Ang1 also decreased the CsA-induced increases in TGF-beta1 and Smad 2/3 levels while increasing Smad 7 levels. Laser-Doppler sonographic findings and endothelial factor VIII staining revealed that COMP-Ang1 preserved the integrity of peritubular vasculature and intrarenal haemodynamics from the CsA-induced renal injury. COMP-Ang1 inhibited tubular cell apoptosis while increasing tubular cell proliferation in CsA-induced renal injury.

CONCLUSIONS

These results indicate that COMP-Ang1 exhibited a protective effect on damaged peritubular capillaries, haemodynamic alteration and inflammation in CsA-induced renal injury. Thus, COMP-Ang1 may be useful as a therapeutic and prophylactic agent for specific protection against endothelial dysfunction and inflammation.